1. Field of the Invention
The present invention is related to breakwaters or wave reducing structures used to create a calm region on a liquid surface. More specifically, the invention is related to wave reducing structures which is made of a resilient material, submerged under the liquid at the boundary of the region and restrains waves from propagating over the boundary. The present invention is also related to a method of constructing the submerged flexible wave reducing structure.
2. Prior Arts
It is sometimes needed to create a calm region on a water surface by reducing outside waves from getting inside over the boundary. A typical example is a breakwater or a jetty at a harbor which is constructed to protect ships moored inside. But the same needs exist also in other occasions, such as, at a construction site of marine structures where a safety has to be secured, at a waterfront which has to be protected from wave errosion or at a marine amusement area where marine sports such as water skiing are to be performed.
Breakwaters currently in use comprise breakwaters outstanding out of the water surface and breakwaters submerged under the water. Conventional breakwaters are further classified, according to its material, to stone structures, reinforced concrete structures and piled up concrete block structures. Breakwaters outstanding out of water surface are used when it is needed to almost perfectly isolate the region from the outside waves. Submerged breakwaters are used when the propagation of waves into the region is acceptable to some extent. These conventional breakwaters are effective but their disadvantages are that they are costly, take much time for construction and are difficult to remove when needed. Further, they obstruct the navigation of ships and are sometimes dangerous for ships passing around them because the ships may be thrown against the breakwater or pushed to get wrecked on the submerged breakwater by the waves.
Conventional breakwaters are constructed by casting concrete in place, by laying down pre-fabricated caissons or by piling up pre-fabricated concrete blocks. These methods require much labor and time because a large amount of materials have to be transported and large quantity of work has to be done on site. Therefore, construction of breakwaters costs very high as far as these conventional structures and conventional construction methods are employed.